Ericsson unleashes LTE over the Wi-Fi airwaves

Carriers are constantly on the hunt for more 4G spectrum, but the airwaves they need may be right under their noses. Mobile network builder Ericsson has developed a new technology that allows carriers to add Wi-Fi spectrum to their LTE networks, boosting overall capacity and the raw speeds available to our smartphones, tablets and mobile hotspots.

The technology is called License Assisted Access (LAA) and it’s been worked on by wireless networking companies across the mobile industry, but at CES on Monday [company]Ericsson[/company] said it has a version of its small cell in the pipeline that takes advantage of LAA. A small cell is basically a big tower-mounted cell in miniature, and they’re used to surgically insert more capacity the network. By adding LAA to small cells, carriers would be able to amp up data speeds to their customers in the most high-demand places, particularly indoors where most mobile data is consumed.

Small cells would add surgical capacity to the most high demand areas of the network (source: Gigaom / Rani Molla)

Small cells would add surgical capacity to the most high demand areas of the network (source: Gigaom / Rani Molla)

LAA makes use of another LTE technology we’ve been hearing more and more about overseas and at home: carrier aggregation, which bonds together LTE transmissions from different bands. Instead of gluing together two traditional LTE networks over licensed spectrum, LAA tops off the network with any 5GHz unlicensed frequencies that aren’t being used at any given moment.

Basically, LAA will make LTE function under the same principles as Wi-Fi today: Any network can use the airwaves — they just have to coordinate to avoid interfering for one another. That means an LAA small cell will constantly be scanning the unlicensed airwaves looking for free channels. When it finds one it sets up its 4G connection.

Of course, anyone who has ever been in a crowded Wi-Fi environment – for instance, a big tech show like CES – knows that those airwaves can quickly become overcrowded. That’s the inherent limitation of LAA, Ericsson’s head of LTE mobile broadband Eric Parsons explained: since carriers don’t have exclusive access to the unlicensed airwaves they’re never guaranteed any set level of bandwidth.

But Parsons pointed out that an LAA network would never be crippled the same way a Wi-Fi network would because it still has access to the carrier’s underlying LTE network on licensed airwaves.

Let’s use [company]T-Mobile[/company] as an example. Its regular LTE network in Dallas used 20 MHz of its own Advanced Wireless Service spectrum for downlink communications, supporting a theoretical speed of 150 Mbps. That baseline capacity would always be available to T-Mobile’s customers, but with LAA the small cell could add another 20 MHz of unlicensed frequencies to that downlink. Depending on how crowded those airwaves are with Wi-Fi at the moment that additional speed might be as little as few megabits per second, but it could be as great as 150 Mbps, effectively doubling the network’s capacity to 300 Mbps, Parsons said. The network will always serve its licensed airwaves up as a main course, but any additional capacity it gets from LAA will be gravy.

Mobilize 2012 Neville Ray T-Mobile

Neville Ray, CTO, T-Mobile, speaking at Gigaom’s Mobilize conference (c) 2012 Pinar Ozger [email protected]

T-Mobile isn’t just a convenient example, it’s also an active backer of the technology. In a blog post today, T-Mobile CTO Neville Ray said he plans to use LAA in his network designs once the technology matures. When that happens will be hard to say though. While Ericsson said its LAA small cell will be available for commercial network rollouts this year, the mobile industry still has to release mobile phones and devices that can tap these new LTE frequencies.

But once LAA comes, Ray pointed out, mobile carriers would have a powerful new toy to build raw speed into their networks. Look at it this way: They typical LTE network today uses 40 MHz of spectrum. The unlicensed bands have 550 MHz of usable frequencies.


SK Telecom glues together 3 LTE networks, hitting 300 Mbps speeds

SK Telecom is starting the new year with a new kind of 4G network – or at least a network built from the pieces of its older LTE systems. This week, SK turned on a 300 Mbps LTE service that ties together spectrum from three different frequency bands.

The network uses an LTE-Advanced technique called carrier aggregation to bond together 4G channels to create a kind of super-connection. [company]SK Telecom[/company] was one of the first operators to use carrier aggregation technology, bonding two 4G transmissions together back in 2013 to hit 150 Mbps. At the time, it jumped the gun a bit by calling its network LTE-Advanced, when in truth it wasn’t building anything more powerful than most LTE services in Europe.

But by using tri-band carrier aggregation, SKT is now making the leap to speeds that plain old LTE could never reach. It’s combining 20 MHz in the 1800 MHz band with 10 MHz in each of the 2.1 GHz and 800 MHz bands, and coordinating their transmissions so they act like a unified downlink pipe.

As SKT gets access to more spectrum in those bands it can boost speeds and capacities further. The U.K.’s [company]Everything Everywhere[/company] is already testing a network in London with [company]Huawei[/company] and [company]Qualcomm[/company] that hits 410 Mbps, while SK itself has used tri-band tech to hit 450 Mbps in demos. SK said it is already working on combining four and even five frequency bands.

Though SKT claims the new network is now commercial launched, it doesn’t appear to be widely available just yet. The operator said it plans to upgrade 26,000 cell sites in the Seoul metro area and the centers of other South Korean cities in the first quarter. It also plans to offer the new tri-band capabilities in all of the country’s subway lines.

As for devices, per usual the SKT is ahead of the curve. [company]Samsung[/company] has made a version of Galaxy Note 4 that appears to be specifically optimized for the Korean network, and SK said it would offer those oversized handsets to a limited group on customers to help it test and improve the service. The first widely available devices with tri-band aggregation support should be coming out in the next six months, according to Qualcomm.

EE’s UK network tests push LTE speeds to 410 Mbps

U.K. carrier Everything Everywhere has managed to squeeze a 410 Mbps LTE connection out of a 4G trial, generating speeds nearly 50 percent faster than its new souped-up “4G+” network in London. We’re still a couple of years away from such raw speeds in the wild, but these tests show what’s in store for consumers as the mobile industry takes up new LTE-Advanced technologies.

EE had plenty of help from [company]Qualcomm[/company], which builds the cellular modems inside of smartphones and tablets, and its network supplier Huawei. The companies supplied device and network technology that supports a new iteration of the LTE standard called Category 9, which uses a technique called carrier aggregation to bond together LTE transmissions in disparate frequency bands to create a kind of super-connection.

Many carriers around the world already have begun using carrier aggregation to tie together two LTE transmissions, but Category 9 chips will combine the bandwidth of three different frequency channels, creating a downlink up to 60 MHz wide that could potentially support speeds up to 450 Mbps. EE has already used carrier aggregation to build a 40 MHz network, but Category 9 gear is allowing it to tack on an additional 15 MHz of bandwidth in the 2.6 GHz band.

We’ll likely see other trials of the technology in the coming year, and not just in Europe and Asia. Though U.S. operators have been slow to adopt carrier aggregation, they’re deploying new 4G networks all over the frequency map. Both [company]Verizon[/company] and [company]AT&T[/company] now have second and third LTE networks in the Advanced Wireless Service and PCS bands. Meanwhile, [company]Sprint[/company] has a boatload of spectrum allocated for its new Spark 4G service. It just needs carrier aggregation to tie all of those frequencies together.

T-Mobile pushes LTE to the outskirts of 4 cities

T-Mobile’s 4G network may not have the geographical reach of Verizon’s, but T-Mobile has started taking the first steps to get there. In conjunction with its big rollover data announcement on Tuesday, T-Mobile revealed that its new LTE network on the 700 MHz band is now live in and outside of Cleveland, Colorado Springs, Minneapolis and Washington, D.C.

[company]T-Mobile[/company] has offered LTE services in those cities since 2013, but by tapping into new 700 MHz frequencies it bought from Verizon, it’s been able to create a higher-coverage, better-performing network. T-Mobile’s main LTE network is up in the 1700 MHz/2100 MHz band, but lower bands can propagate further, letting signals punch through walls and travel further in suburban and rural areas.

The big knock on T-Mobile is that its coverage has always been so poor compared to [company]AT&T[/company] and [company]Verizon[/company]. That’s a comparison T-Mobile wants to nullify as this new network gets rolled out, T-Mobile CEO John Legere said in a call with media Tuesday.

“I can’t tell you the exact month, but I can tell you that we won’t stop until we have a complete network,” Legere said.

CTO Neville Ray said that T-Mobile is using the spectrum to build an overlay in metro areas as well as expand the edges of its 4G coverage much further outside of cities than it has in the past. For example, in Washington, D.C., T-Mobile has used 700 MHz to go well beyond the Beltway, expanding into western suburbs and even outlying rural areas. Ray estimated that the upgrade has increased T-Mo’s LTE coverage by 30 to 40 percent in the D.C. region alone.

Today T-Mobile’s LTE systems cover 260 million people, but the 700 MHz upgrade will put 300 million people under its 4G umbrella. Most of that will be accomplished by bringing mobile broadband to the regions between cities it’s typically served only with 2G networks, Ray added.

Ray also said that T-Mobile’s new higher-capacity wideband LTE network is now available in 121 cities, including the newly launched New York City network. Wideband LTE T-Mobile increases 4G speeds and capacity by 50 percent in most cases, and in some cities it’s doubling bandwidth.

Verizon starts killing off 3G networks to make room for LTE

Verizon has already launched two distinct LTE networks since it first turned on 4G in 2010, but now it’s started paving the way for the third. Unlike the first two, however, this new network won’t tap virgin airwaves. Instead Verizon has started cannibalizing its old CDMA EV-DO systems for PCS spectrum, marking the beginning of what will likely be a very slow death for 3G.

Gigaom’s favorite network spotter Milan Milanovic discovered signs of [company]Verizon[/company]’s new LTE network in Manhattan when he connected to it with a Nexus 5 (a device Verizon traditionally hasn’t supported because it doesn’t work over its primary 4G network) and a Galaxy S4. The 1980MHz/1990MHz chunk of frequencies has traditionally been part Verizon’s 3G EV-DO network, or it was until last month when Milanovic noticed it was turned off (Milanovic happens to be kind of guy who totes around an industrial spectrum analyzer.)

A spectrum analyzer shows LTE signals in portion of the 1900 MHz PCS band that formerly contained CDMA EV-DO.

A spectrum analyzer shows LTE signals in portion of the 1900 MHz PCS band that formerly contained CDMA EV-DO.

This week, though, Milanovic noticed that those empty airwaves had once again jumped back to life, but with LTE instead of CDMA signals. Milanovic said that he’s found Verizon LTE in the PCS band at cell sites all over Manhattan, but so far nothing in Brooklyn and Queens. The transmit power of the network is still very low and the internet speeds he’s getting are still very slow, he said, indicating that Verizon is still in the early stages of testing. There have also been reports on network-tracking site SG4U of LTE popping up on Verizon’s PCS band in Cleveland.

I pinged Verizon, and spokeswoman Debra Lewis confirmed that Verizon is indeed testing LTE on the PCS band, though she said Verizon wouldn’t go into any specifics on locations or timing for a commercial launch. Lewis also made the point that this should hardly come as surprise since Verizon has said it would begin repurposing a portion of its 3G bandwidth for LTE in 2015. In fact, as early as 2011, Verizon CTO Tony Melone told me Verizon would likely shut down 3G completely as all of Verizon’s data traffic moved over to 4G networks.

That day is still a long time coming, though. About 80 percent of Verizon’s mobile data traffic now rides over LTE, but some 40 million (41 percent) of the total devices on Verizon’s networks only have 2G and 3G radios. That means for the foreseeable future, Verizon will have to keep a modicum of EV-DO capacity online at every cell site to support those devices. That’s what we’re starting to see in NYC at least: Verizon appears to have shut off half of its upper-band 3G capacity across Manhattan.

As for 2G, it will be around even longer than 3G since it’s still Verizon’s primary voice network, but eventually Verizon will begin the bulk of its voice traffic onto its new voice-over-LTE service. What we’re witnessing is the very beginning of a long, slow march toward death for Verizon 3G and the gradual transformation of Verizon into a carrier providing all its voice and data services over a single network technology.